INT 15,C0 - Return System Configuration Parameters (PS/2 only)

	AH = C0

	on return:
	CF = 0 if successful
	   = 1 if error
	AH = when CF set, 80h for PC & PCjr, 86h for XT
	     (BIOS after 11/8/82) and AT (BIOS after 1/10/84)

	ES:BX = pointer to system descriptor table in ROM of the format:

	Offset Size	     Description

	  00   word   length of descriptor (8 minimum)
	  02   byte   model byte (same as F000:FFFE, not reliable)
	  03   byte   secondary model byte
	  04   byte   BIOS revision level (zero based)
	  05   byte   feature information, see below
	  06   dword  reserved


	Feature Information

	│7│6│5│4│3│2│1│0│  Feature Byte
	 │ │ │ │ │ │ │ └──── reserved
	 │ │ │ │ │ │ └───── 0=PC bus, 1=Micro Channel
	 │ │ │ │ │ └────── Extended BIOS Data Area (EBDA)allocated
	 │ │ │ │ └─────── wait for external event supported
	 │ │ │ └──────── INT 15,4F used (kbd intercept)
	 │ │ └───────── RTC present
	 │ └────────── 2nd 8259 present
	 └─────────── DMA channel 3 used by fixed disk BIOS

	- see	MACHINE ID